The present invention relates to an apparatus for supplying oxygen; and, more particularly, to an oxygen-rich gas supplying device having an atmospheric air passage and a valve assembly for closing and opening the atmospheric air passage.
There are many apparatuses used to supply oxygen. Such apparatuses typically filter nitrogen from ambient air by using zeolite that serves as an absorbent. Since the zeolite is capable of absorbing the nitrogen, a bed filled with the zeolite can be used to capture the nitrogen in the air introduced therein, thus producing an oxygen-rich gas. The oxygen-rich gas flowing from a discharge point of the bed is collected in a product tank.
Each apparatus for supplying oxygen by utilizing such beds as described above includes an oxygen-rich gas supplying device that discharges through which the oxygen-rich gas is discharged. The oxygen-rich gas supplying device is provided with an oxygen sensor, which gauges oxygen concentration of the oxygen-rich gas supplied therethrough.
The oxygen sensor is calibrated to set a reference value therefor before being used for gauging the oxygen concentration. Further, since a sensing ability of the oxygen sensor is deteriorated while being used, it is required that the oxygen sensor be calibrated periodically during a long-time usage to set a new reference value.
It is one method for calibrating the oxygen sensor to expose the oxygen sensor to an atmospheric air since the oxygen concentration of the atmospheric air is known to be 20.9% and the reference value can be set by using this value.
The conventional apparatuses for supplying oxygen, however, have a drawback. Since the oxygen sensor for gauging the oxygen concentration of the oxygen-rich gas discharged through the oxygen-rich gas supplying device is disposed inside the oxygen-rich gas supplying device, the oxygen-rich gas is stacked around the oxygen sensor even after the supply of the oxygen-rich gas to the oxygen-rich gas supplying device is cut off. As a result, during calibration the oxygen sensor may still be exposed to the oxygen-rich gas and consequently the calibration of the oxygen sensor performed will have a large error.
It is, therefore, an object of the present invention to provide an apparatus for supplying oxygen having an oxygen-rich gas supplying device capable of supplying atmospheric air toward a detecting portion of an oxygen sensor incorporated in the oxygen-rich gas supplying device so as to calibrate the oxygen sensor more precisely.
In accordance with the present invention, there is provided an apparatus for supplying oxygen, including: an oxygen-rich gas supplying unit for discharging an oxygen-rich gas, including a first passage through which the oxygen-rich gas flows, a side surface of the first passage having an opening formed therein, a second passage through which an atmospheric air flows, one end of the second passage is attached to a periphery of the opening formed in the side surface of the first passage in such a manner that the first passage communicates with the second passage, an oxygen sensor for measuring an oxygen concentration of the oxygen-rich gas flowing through the first passage and installed in the side surface of the first passage in such a manner that a detecting portion of the oxygen sensor is exposed in an inside of the passage, and a valve assembly for closing and opening the second passage and attached to the second passage, wherein the oxygen concentration of the oxygen-rich gas is greater than that of the atmospheric air.